Algebra is a branch of Maths in which we use letters
represent numbers. We do this when we do not what
the number is .We give the number a letter and the
use an equation to find the value of the number.
For example:
If we give an unknown number the letter x and we
know that x+3 = 7 .We take 3 from each side of the
equation we get x + 3 -3 = x
and 7 -3 = 4
Therefore x = 4